<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        #box1{
            width: 200px;
            height: 200px;
            background: red;
        }
        #box2{
            width: 100px;
            height: 100px;
            background: blue;
        }
    </style>
</head>

<body>
    <div id="box1">
        <div id="box2"></div>
    </div>
    <script>
        var box1 = document.querySelector("#box1");
        var box2 = document.querySelector("#box2");

        box1.onclick = function () {
            console.log("这是BOX1");
        }
        box2.onclick = function (e) {
            e.stopPropagation();
            console.log("这是BOX2");
        }
    </script>
</body>

</html>